Plays are literature: the word, the idea. Film is much more like the form in which we dream - in action and images (Television is furniture). I think a great play can only be a play. It fits the stage better than it fits the screen. Some stories insist on being film, can't be contained on stage. In the end, all writing serves to answer the same question: Why are we alive? And the form the question takes - play, film, novel - is dictated, I suppose, by whether its story is driven by character or place.